MRI versus histological methods for time course monitoring of steatosis amount in a murine model of NAFLD.

PURPOSE: Hepatic steatosis is an increasingly frequent disease with potentially severe complications. A simple quantification method is required for pretherapeutic studies to allow steatosis monitoring. This study aimed at evaluating steatosis quantification via a standard 1.5T MRI machine in a murine model. MATERIALS AND METHODS: Eleven groups of two rats received a choline methionine deficient diet. MRI was performed at days 0, 2, 4, 5, 6, 7 and 8, and weeks 2, 3, 4 and 5. A phased array surface coil system was used to acquire a GE T1 in- and out-of-phase multi-echo sequence, with neither cardiac nor respiratory synchronization. Steatosis was calculated with the 3-echoes method. Histological quantifications were performed both by optical analysis (percentage of fatty hepatocytes) and by automated measurement of the area of steatosis (AOS). The reference was total intrahepatic triglycerides (TIT). Protocol was approved by the ethic committee. RESULTS: Steatosis without inflammation, increasing with diet duration, was obtained. MRI provided better agreement (intraclass correlation coefficient) with TIT (0.889, p<0.001) than did AOS (0.629, p=0.001) or optical analysis (0.280, p=0.098). MRI permitted closer monitoring of TIT over time than did AOS or optical analysis. By multivariate analysis, MRI was an independent predictor of TIT on first step and ALT on second step. A model combining these 2 variables provided excellent agreement with TIT (0.953, p<0.001) and permitted excellent monitoring of steatosis over time. CONCLUSION: MRI is reliable, easy, fast and superior to histological techniques for the assessment of hepatic steatosis in a murine model.

MRI measurement of liver fat content predicts the metabolic syndrome.

BACKGROUND AND AIMS: The prevalence of non-alcoholic fatty liver disease among cardiometabolic patients is not completely known because liver biopsy cannot be routinely performed. However, as magnetic resonance imaging (MRI) allows accurate and safe measurement of the hepatic fat fraction (HFF), the aim of this study was to quantify liver fat content in a dysmetabolic adult population. METHODS: A total of 156 adults were included in this cross-sectional study. Liver and visceral fat were assessed by MRI in these subjects, who presented with zero to five metabolic components of the metabolic syndrome (MetS). Arterial stiffness was recorded by ultrasonography, and the maximum Youden index was used to set the optimal HFF cutoff value predictive of the presence of the MetS. RESULTS: Overall, 72% of participants displayed three or more MetS components. HFF ranged from 0.3% to 52% (mean 13.4%). Age- and gender-adjusted HFF was positively correlated with BMI (r=0.44), blood pressure (r=0.19), triglyceridaemia (r=0.22) and glycaemia (r=0.31). MRI-measured visceral adipose tissue did not influence the relationship of steatosis with glycaemia, HOMA-IR and carotid stiffness, but there was a dose-response relationship between the number of MetS components and mean HFF. The optimal HFF for predicting the MetS was found to be 5.2% according to the maximum Youden index point. CONCLUSION: This study highlighted the impact of liver steatosis on cardiometabolic abnormalities with an optimal cutoff value of 5.2% for defining increased metabolic risk.

Distribution of abdominal adipose tissue as a predictor of hepatic steatosis assessed by MRI.

AIM: To evaluate the relationship between the distribution of visceral and subcutaneous adipose tissue and hepatic steatosis assessed using magnetic resonance imaging (MRI). MATERIALS AND METHODS: One T1-weighted, in-/out-of-phase, single-section sequence at the L3/L4 level and one multi-echo gradient MRI (MGRE) sequence were performed on 65 patients [19 females and 46 males; age 57+/-9.5 years; body mass index (BMI) 31+/-5.1kg/m(2)]. Visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT) surfaces, and hepatic steatosis were automatically calculated using in-house software. Weight, height, BMI, waist circumference, hip circumference, and waist:hip ratio were recorded. The probability of having a steatosis greater than 10% on MRI was evaluated by receiver operating characteristic (ROC) curves. RESULTS: The anthropometric parameter best correlated to hepatic steatosis was the waist-to-hip ratio (r=0.301). VAT and proportion of VAT were correlated to liver fat content (r=0.307 and r=0.249, respectively). No significant correlations were found for BMI, hip circumference, and SAT. The area under the receiver operating characteristics (AUROCs) for the relationship between liver steatosis and BMI, waist circumference, waist:hip ratio, VAT surface, and proportion of VAT, were respectively 0.52, 0.63, 0.71, 0.73 and 0.75. CONCLUSION: Adipose tissue distribution is more relevant than total fat mass when assessing the possibility of liver steatosis in overweight patients.

[Interference of ethylene glycol on lactate assays]. / Interférences des métabolites de l'éthylène glycol avec les dosages du lactate.

Ethylene glycol is broken down to three main organic acids: glycolic acid, glyoxylic acid and oxalic acid which cause severe metabolic acidosis. Effect of these three acids on lactate assays was evaluated in five blood gas analysers and two clinical chemistry analysers. For all systems, no influence of oxalic acid on lactate results could be demonstrated. No interference of glycolic acid could be observed on lactate assay performed with Rapid Lab 1265 (R: 104,9 +/- 12,1%), Vitros 950 (R: 105,7 +/- 5,3 %) and Architect ci8200 (R: 104,9 +/- 4,7%), but on the contrary, CCX 4, OMNI S, ABL 725 and 825 demonstrated a concentration-dependent interference. No interference of glyoxylic acid could be observed with Vitros 950, but a positive interference could be observed with ABL 725 and 825, OMNI S, CCX4 and Architect ci8200 A linear relationship between apparent lactate concentration found with ABL 725 and 825, OMNI S, CCX 4, and glyoxylic acid could be observed (0,94 < r < 0,99), a weaker interference being observed with Rapid Lab 1265 and Architect ci 8200. Our results demonstrated that in case of ethylene glycol poisoning, cautious interpretation of lactate assay should be done, since wrong results of lactacidemia could lead to misdiagnostic and delay patient treatment.